Polyethylene composition and process for polymerizing the same

ABSTRACT

The instant invention provides a polyethylene composition and process for polymerizing the same. 
     The polyethylene composition according to the present invention comprises the polymerization reaction of ethylene and optionally one or more α-olefin comonomers in the presence of a catalyst system, wherein said polyethylene composition comprises at least 2 or more molecular weight distributions, measured via triple detector GPC low angle laser light scattering (GPC-LALLS), described in further details hereinbelow, wherein each molecular weight distribution has a peak, and wherein measured detector response of peak 1 divided by the measured detector response of peak 2 is in the range of from 0.50 to 0.79, for example from 0.55 to 0.77.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is filed as a divisional of U.S. application Ser. No.14/900,445 filed on Dec. 21, 2015, which is a national stage entry ofPCT/US2014/043757 file on Jun. 24, 2014, which claims priority to U.S.Provisional Application Ser. No. 61/841,323 filed on Jun. 29, 2013, allof which are incorporated herewith.

FIELD OF INVENTION

The instant invention relates to a polyethylene composition and processfor polymerizing the same.

BACKGROUND OF THE INVENTION

The use of Ziegler-Natta catalyst systems to promote various olefinpolymerizations is well known. These catalyst systems typically includea catalyst precursor comprising one or more of each of a transitionmetal, an electron donor or ligand and a cocatalyst. Complete or nearcomplete activation of the precursor is necessary in order to obtain thehigh-level of catalyst activity required for a commercial olefinpolymerization process. Catalyst activation can consist of multiplesteps which may include chlorination, reduction reactions, displacementof internal electron donors or ligands and other chemical modificationsto the catalyst precursor that are necessary to obtain high levels ofcatalyst productivity. Other catalyst attributes are also affected bythe catalyst activation process; such as stereoregulation (for propyleneand butene polymerization), molecular weight distribution, comonomerincorporation and the like. It is well known in the art that these keycatalyst attributes are affected by a number of variables, including themethod of catalyst manufacture or formation, the use of internalelectron donors, the chemical composition of the internal electrondonor, the use of external electron donors and the amount of theelectron donors present.

Activation of the catalyst precursor requires the removal of theinternal electron donor from the vicinity of the active site, i.e., themetal, and, if necessary, reduction of the metal. The activator extractsthe internal electron donor compound from the active site in one ofseveral ways. The internal donor can be removed by complex formation,typically with a Lewis Acid, or by alkylation or by reduction andalkylation if the valence state of the metal requires reduction. Typicalactivating compounds are Lewis Acids.

Activation of the catalyst precursor may occur by (i) full activation inthe polymerization reactor by the cocatalyst, (ii) partial activationbefore introduction of the precursor into the reactor and completion ofthe activation in the reactor by means of the cocatalyst, or (iii) fullactivation prior to introduction of the precursor into the reactor.There are several advantages and disadvantages to all three techniques.

Complete activation of the catalyst inside the polymerization reactortypically requires a substantial excess of activator compound and in thecase of higher (C₃, C₄ and up) olefin polymerizations, use of excessselectivity control agent. Advantages to this technique are itssimplicity of catalyst manufacture and feed. However, excess activatorcompound is not only an added operational expense, but it may causeoperational problems or detriment to the final product. In addition,there is no way to modify the catalyst composition in an on-line fashionto significantly affect the polymerization response.

Partial activation of the catalyst precursor outside of the reactorrequires additional process steps and equipment followed by finalactivation in the reactor (which, again, requires the use of excessiveamounts of activator). Partial activation outside of the reactor alsoresults in the need to store the partially activated catalyst and thelikelihood of catalyst deactivation during storage, either due tocontinued reactions with the activator compounds and their reactionproducts or due to impurities invariably present in inert gases (such asnitrogen) typically used to blanket these catalysts during storage.Although the formulation of the catalyst may be changed in the partialactivation procedure external to the reactor, this again results in astatic catalyst formulation. Any polymerization response changes canonly come from changing the catalyst batch. Currently, there is noon-line control technique available for fine control of the molecularweight distribution of desired polymers.

SUMMARY OF THE INVENTION

The instant invention provides a polyethylene composition and processfor polymerizing the same.

In one embodiment, the instant invention provides a polyethylenecomposition comprising the polymerization reaction product of ethyleneand optionally one or more α-olefin comonomers in the presence of acatalyst system, wherein said polyethylene composition comprises atleast 2 or more molecular weight distributions, measured via tripledetector GPC low angle laser light scattering (GPC-LALLS), wherein eachmolecular weight distribution has a peak, and wherein measured detectorresponse of peak 1 divided by the measured detector response of peak 2is in the range of from 0.50 to 0.79, for example, from 0.55 to 0.77.

In an alternative embodiment, the instant invention further provides aprocess for polymerizing a polyethylene composition comprising the stepsof:

(A) Preparing a slurry of a precursor and a viscous inert liquid, saidslurry having a viscosity of at least about 500 cp, the precursorcomprising (i) a ligand; (ii) a transition metal; and (iii) a firstLewis Base;

(B) Contacting the slurry of (A) with a first Lewis Acid such that atleast a portion of the Lewis Base is complexed with the Lewis Acidwherein the Lewis Acid has the formula MR_(n)X_((m−n)), M is Al, B orSi, R is a C1 to C14 alkyl or aryl radical, X is Cl, Br or I, m+nsatisfies the valency of the metal M, n is 0 to 3;

(C) Contacting the slurry of (B) with a second different Lewis Acid withthe formula MR_(n)X_((m−n)), M is Al, or B, R is a C1 to C14 alkyl oraryl radical, X is Cl, Br or I, m+n satisfies the valency of the metalM, n is 0 to 2;

(D) Feeding the slurry of (C) into a gas phase reactor in which anolefin polymerization reaction is in progress in the presence ofoptionally one or more cocatalysts and wherein the molar ratios of LewisAcid 1 and Lewis Acid 2 to the electron donor are controlled to affectspecific fractions of the molecular weight distribution of the finalpolymer product;

(E) Where both the relative ratio of Lewis Acid (1) and Lewis Acid (2)to internal electron donor and the chemical identity of Lewis Acid (1)and (2) is adjusted to polymerize said polyethylene composition, whereinsaid polyethylene composition comprises at least 2 or more molecularweight distributions, measured via triple detector GPC low angle laserlight scattering (GPC-LALLS), wherein each molecular weight distributionhas a peak, and wherein measured detector response of peak 1 divided bythe measured detector response of peak 2 is in the range of from 0.50 to0.79.

In another alternative embodiment, the instant invention furtherprovides an article comprising the inventive polyethylene composition.

In an alternative embodiment, the instant invention provides an article,in accordance with any of the preceding embodiments, except that thearticle is produced via rotational molding, thermoforming, blow molding,or injection molding.

In an alternative embodiment, the instant invention provides a processfor polymerizing a inventive polyethylene composition, in accordancewith any of the preceding embodiments, except that the process occurs ina single gas phase reactor, or a dual gas phase reactor.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there is shown in thedrawings a form that is exemplary; it being understood, however, thatthis invention is not limited to the precise arrangements andinstrumentalities shown.

FIG. 1 shows a schematic flow chart of on-line in-line catalystactivation system; and

FIG. 2 is a graph illustrating the relationship peak height ratio v.density v. catalyst for Comparative Examples 1-13 and Inventive Examples1-13; and

FIG. 3 is a graph illustrating the relationship between the peak heightratio of the Comparative Examples 1-13 and the peak height ratio of theInventive Examples 1-13.

FIG. 4 is a gel permeation chromatography (GPC) low angle laser lightscattering (LALLS) scan in which the molecular weight distribution ismeasured, intensity versus retention volume.

FIG. 5 is a GPC-LALLS scan in which the molecular weight distribution ismeasured, intensity versus retention volume.

FIG. 6 is a GPC-LALLS scan in which the molecular weight distribution ismeasured, intensity versus retention volume.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention provides a polyethylene composition and processfor polymerizing the same.

The polyethylene composition according to the present inventioncomprises the polymerization reaction of ethylene and optionally one ormore α-olefin comonomers in the presence of a catalyst system, whereinsaid polyethylene composition comprises at least 2 or more molecularweight distributions, measured via triple detector GPC low angle laserlight scattering (GPC-LALLS), described in further details hereinbelow,wherein each molecular weight distribution has a peak, and whereinmeasured detector response of peak 1 divided by the measured detectorresponse of peak 2 is in the range of from 0.50 to 0.79, for examplefrom 0.55 to 0.77.

The process for polymerizing a polyethylene composition according to thepresent invention comprises the steps of:

(A) Preparing a slurry of a precursor and a viscous inert liquid, saidslurry having a viscosity of at least about 500 cp, the precursorcomprising (i) a ligand; (ii) a transition metal; and (iii) a firstLewis Base;

(B) Contacting the slurry of (A) with a first Lewis Acid such that atleast a portion of the Lewis Base is complexed with the Lewis Acidwherein the Lewis Acid has the formula MR_(n)X_((m−n)), M is Al, B orSi, R is a C1 to C14 alkyl or aryl radical, X is Cl, Br or I, m+nsatisfies the valency of the metal M, n is 0 to 3;

(C) Contacting the slurry of (B) with a second different Lewis Acid withthe formula MR_(n)X_((m−n)), M is Al, or B, R is a C1 to C14 alkyl oraryl radical, X is Cl, Br or I, m+n satisfies the valency of the metalM, n is 0 to 2;

(D) Feeding the slurry of (C) into a gas phase reactor in which anolefin polymerization reaction is in progress optionally in the presenceof one or more cocatalyst and wherein the molar ratios of Lewis Acid 1and Lewis Acid 2 to the electron donor are controlled to affect specificfractions of the molecular weight distribution of the final polymerproduct;

(E) Where both the relative ratio of Lewis Acid (1) and Lewis Acid (2)to internal electron donor and the chemical identity of Lewis Acid (1)and (2) is adjusted to polymerize said polyethylene composition, whereinsaid polyethylene composition comprises at least 2 or more molecularweight distributions, measured via triple detector GPC low angle laserlight scattering (GPC-LALLS), wherein each molecular weight distributionhas a peak, and wherein measured detector response of peak 1 divided bythe measured detector response of peak 2 is in the range of from 0.50 to0.79, for example from 0.55 to 0.77.

In another alternative embodiment, the instant invention furtherprovides an article comprising the inventive polyethylene composition.

In an alternative embodiment, the instant invention provides an article,in accordance with any of the preceding embodiments, except that thearticle is produced via rotational molding, thermoforming, blow molding,or injection molding.

In an alternative embodiment, the instant invention provides a processfor polymerizing a inventive polyethylene composition, in accordancewith any of the preceding embodiments, except that the process occurs ina single gas phase reactor, or a dual gas phase reactor.

According to the invention, a slurry of a precursor and a viscous inertliquid, said slurry having a viscosity of at least about 500 cp isprepared. Within the scope of the present application, the term“precursor” denotes a compound comprising a ligand, a transition metal,and a first Lewis Base. Such precursor catalysts are commonly referredto as Ziegler-Natta catalysts. Suitable Zeigler-Natta catalysts areknown in the art and include, for example, the catalysts taught in U.S.Pat. Nos. 4,302,565; 4,482,687; 4,508,842; 4,990,479; 5,122,494;5,290,745; and, 6,187,866 B1, the disclosures of which are herebyincorporated by reference, to the extent that they disclose suchcatalysts.

The transition metal compound of the precursor composition can comprisecompounds of different kinds. The most usual are titaniumcompounds—organic or inorganic—having an oxidation degree of 3 or 4.Other transition metals such as, vanadium, zirconium, hafnium, chromium,molybdenum, cobalt, nickel, tungsten and many rare earth metals are alsosuitable for use in Ziegler-Natta catalysts. The transition metalcompound is usually a halide or oxyhalide, an organic metal halide orpurely a metal organic compound. In the last-mentioned compounds, thereare only organic ligands attached to the transition metal.

The precursor can have the formula Mg_(d) Me(OR)_(e) X_(f)(ED)_(g)wherein R is an aliphatic or aromatic hydrocarbon radical having 1 to 14carbon atoms or COR′ wherein R′ is a aliphatic or aromatic hydrocarbonradical having 1 to 14 carbon atoms; each OR group is the same ordifferent; X is independently chlorine, bromine or iodine; ED is anelectron donor; d is 0.5 to 56; e is 0, 1, or 2; f is 2 to 116; and gis >1 to 20. Me is a transition metal selected from the group oftitanium, zirconium, hafnium and vanadium. Some specific examples ofsuitable titanium compounds are: TiCl₃, TiCl₄, Ti(OC₂H₅)₂Br₂,Ti(OC₆H₅)Cl₃, Ti(OCOCH₃)Cl₃, Ti(acetylacetonate)₂Cl₂,TiCl₃(acetylacetonate), and TiBr₄. TiCl₃ and TiCl₄ are preferredtitanium compounds.

The magnesium compounds include magnesium halides such as MgCl₂, MgBr₂,and MgI₂. Anhydrous MgCl₂ is a preferred compound. Other compoundsuseful in the invention are Mg(OR)₂, Mg(OCO₂Ethyl) and MgRCl where R isdefined above. About 0.5 to about 56, and preferably about 1 to about20, moles of the magnesium compounds are used per mole of transitionmetal compound. Mixtures of these compounds may also be used.

The precursor compound can be recovered as a solid using techniquesknown in the art, such as precipitation of the precursor or by spraydrying, with or without fillers. Spray drying is a particularlypreferred method for recovery of the precursor compound.

Spray drying process is disclosed in U.S. Pat. No. 5,29,0745 and isincorporated by reference. A further precursor comprising magnesiumhalide or alkoxide, a transition metal halide, alkoxide or mixed ligandtransition metal compound an electron donor and optionally a filler canprepared by spray drying a solution of said compounds from an electrondonor solvent.

The electron donor is typically an organic Lewis base, liquid attemperatures in the range of about 0° C. to about 200° C., in which themagnesium and transition metal compounds are soluble. The electron donorcan be an alkyl ester of an aliphatic or aromatic carboxylic acid, analiphatic ketone, an aliphatic amine, an aliphatic alcohol, an alkyl orcycloalkyl ether, or mixtures thereof, each electron donor having 2 to20 carbon atoms. Among these electron donors, the preferred are alkyland cycloalkyl ethers having 2 to 20 carbon atoms; dialkyl, diaryl, andalkylaryl ketones having 3 to 20 carbon atoms; and alkyl, alkoxy, andalkylalkoxy esters of alkyl and aryl carboxylic acids having 2 to 20carbon atoms. For ethylene homo and co-polymerization, the mostpreferred electron donor is tetrahydrofuran. Other examples of suitableelectron donors are methyl formate, ethyl acetate, butyl acetate, ethylether, dioxane, di-n-propyl ether, dibutyl ether, ethanol, 1-butanol,ethyl formate, methyl acetate, ethyl anisate, ethylene carbonate,tetrahydropyran, and ethyl propionate.

While an excess of electron donor may be used initially to provide thereaction product of transition metal compound and electron donor, thereaction product finally contains about 1 to about 20 moles of electrondonor per mole of transition metal compound and preferably about 1 toabout 10 moles of electron donor per mole of transition metal compound.

The ligands comprise halogen, alkoxide, aryloxide, acetylacetonate andamide anions.

The partial activation of the precursor is carried out prior to theintroduction of the precursor into the reactor. The partially activatedcatalyst can function as a polymerization catalyst but at greatlyreduced and commercially unsuitable catalyst productivity. Completeactivation by additional cocatalyst is required to achieve fullactivity. The complete activation occurs in the polymerization reactorvia addition of cocatalyst.

The inert liquid is typically a mineral oil. The slurry prepared fromthe catalyst and the inert liquid has a viscosity measured at 1 sec⁻¹ ofat least 500 cp at 20° C. Examples of suitable mineral oils are theKaydol and Hydrobrite mineral oils from Crompton.

In a preferred mode (referred to as an in-line activation system) shownin FIG. 1, the precursor is introduced into a slurry feed tank 10; theslurry then passes via pump 11 to a first reaction zone 12 immediatelydownstream of a reagent injection port 14 where the slurry is mixed withthe first reagent 16. Optionally, the mixture then passes to a secondreaction zone 22 immediately downstream of a second reagent injectionport 18 where it is mixed with the second reagent 20 in a secondreaction zone 22. While only two reagent injection and reaction zonesare shown on the diagram, additional reagent injection zones andreaction zones may be included, depending on the number of stepsrequired to fully activate and modify the catalyst to allow control ofthe specified fractions of the polymer molecular weight distribution.Means to control the temperature of the catalyst precursor feed tank andthe individual mixing and reaction zones are provided.

Each reaction zone is equipped with static mixers. The static mixers arepreferably positioned vertically. Acceptable mixing can be provided by a2-foot (32-element) Kenics™ static mixer typically used in commercialscale aspects of the invention. This low energy mixer functions byconstantly dividing the flow and reversing flow directions in a circularpattern in the direction of the flow in the tube associated with themixer.

Depending on the activator compound used, some reaction time may berequired for the reaction of the activator compound with the catalystprecursor. This is conveniently done using a residence time zone, whichcan consist either of an additional length of slurry feed pipe or anessentially plug flow holding vessel. A residence time zone can be usedfor both activator compounds, for only one or for neither, dependingentirely on the rate of reaction between activator compound and catalystprecursor.

Particularly preferred activator compounds are aluminum alkyls andaluminum alkyl chlorides of the formula AlR_(x)Cl_(y) where X+Y=3 and yis 0 to 2 and R is a C1 to C14 alkyl or aryl radical. Particularlypreferred activator compounds are given in Table 1. In a particularlypreferred embodiment, one of the two Lewis acids contains at least onehalogen atom.

TABLE 1 Lewis Acid Lewis Acid Diethylaluminum chloride TriethylaluminumEthylaluminum dichloride Trimethylaluminum di-isobutyaluminum chlorideTriisobutylaluminum dimethylaluminum chloride Tri-n-hexylaluminumMethylaluminum sesquichloride Tri-n-octylaluminum Ethylaluminumsesquichloride Dimethylaluminum chloride

The entire mixture is then introduced into the reactor 40 where theactivation is completed by the cocatalyst. Additional reactors may besequenced with the first reactor; however catalyst is typically onlyinjected into the first of these linked, sequenced reactors with activecatalyst transferred from a first reactor into subsequent reactors aspart of the polymerization process.

The cocatalysts, which are reducing agents, conventionally used arecomprised of aluminum compounds, but compounds of lithium, sodium andpotassium, alkaline earth metals as well as compounds of other earthmetals than aluminum are possible. The compounds are usually hydrides,organometal or halide compounds. Conventionally, the cocatalysts areselected from the group comprising Al-trialkyls, Al-alkyl halides,Al-alkoxides and Al-alkoxy halides. In particular, Al-Alkyls andAl-chlorides are used. These compounds are exemplified by trimethylaluminum, triethyl aluminum, tri-isobutyl aluminum, tri-n-hexylaluminum, dimethyl aluminum chloride, diethyl aluminum chloride, ethylaluminum dichloride and diisobutyl aluminum chloride, isobutylaluminumdichloride and the like. Butyl lithium and dibutyl magnesium areexamples of useful compounds of other metals.

In a preferred embodiment, to partially activate the catalyst slurry, asolution of Lewis Acid 1(16) in mineral oil is added as the slurry isbeing pumped to the reactor at mixing location (14) and through a staticmixer (12). This mixture is held in a residence time vessel (20) forroughly 1 to 4 hours, depending on the absolute feed rate of thecatalyst.

Sequentially, then a solution of Lewis Acid 2 in mineral oil is added(26) at mixing location (24) and through a static mixer (22) toresidence time vessel (28) and the mixture is held for roughly 1 to 4hours. The partially activated catalyst then exits the second residencetime vessel and goes directly into the polymerization reactor (40). Aflow aid (46) which comprises nitrogen, a hydrocarbon or a combinationof the two can be used to carry the catalyst into the polymerizationreactor where it is fully activated with a final amount of cocatalyst.

The polyethylene compositions according to the present inventioncomprise at least 2 or more molecular weight distributions, measured viatriple detector GPC low angle laser light scattering (GPC-LALLS),wherein each molecular weight distribution has a peak, and whereinmeasured detector response of peak 1 divided by the measured detectorresponse of peak 2 is in the range of from 0.50 to 0.79. Suchpolyethylene compositions can be formed into various articles via anyconventional known methods, such as rotational molding, thermoforming,blow molding, or injection molding. Such articles can be used as tanks,e.g. water tanks, fuel tanks and the like, toys, recreational articles,e.g. boats, canoes, kayaks, and the like.

EXAMPLES

The following examples illustrate the present invention but are notintended to limit the scope of the invention. The examples of theinstant invention demonstrate that the inventive polyethylenecompositions have enhanced processability while facilitating improvedproperties in the final products.

Inventive Catalyst J₁₋₁₄ and Comparative Catalyst J_(a-m)

Inventive Catalyst J₁₋₁₄ and Comparative Catalyst J_(a-m) were preparedaccording to the following process, based on the formulation componentslisted below.

Catalyst Precursor Preparation Preparation of the Solid CatalystPrecursor:

The solid catalyst precursor is prepared essentially according to theprocess described in example 1 parts (a) and (b) of U.S. Pat. No.5,290,745.

The solid catalyst precursor is prepared in two stages. First, a slurryis produced, and then the slurry is spray dried to obtain the solidcatalyst precursor.

Granulated magnesium metal having a particle size of 0.1 millimetres to4 millimetres is added under nitrogen to an excess of tetrahydrofuran ata temperature of 50° C. such that the weight ratio of magnesium totetrahydrofuran of about 1:800. Titanium (IV) chloride is added to themixture in a mole ratio of magnesium to titanium of 1:2. The mixturetemperature is allowed to rise over a period of 3 hours to a temperatureof 72° C. The reaction mixture is then held at 70° C. for a further 4hours. At the end of this time magnesium dichloride is added so that theratio of magnesium to titanium in the mixture rises to about 5:1. Themixture is held at 70° C. for about 8 hours. The mixture is thenfiltered through a 100 micrometre filter to remove impurities present inthe magnesium chloride.

CAB-O-SIL TS-610 fumed silica (available from Cabot Corporation) actingas an inert filler is then added under nitrogen to the filtered mixtureover a period of two hours, the resulting slurry being stirred by meansof a turbine agitator for several hours thereafter to thoroughlydisperse the fumed silica. The slurry is then sprayed dried undernitrogen at an outlet gas temperature of ˜140 to 160° C. in a closedcycle spray dryer equipped with a rotary atomizer. The rotary atomizerspeed is adjusted to give solid catalyst precursor particles with amedian diameter, D₅₀, of 23 to 27 micrometres. The recycle gas flow rateis in the range of 15-25 kg gas/kg of slurry feed. The spray driedcatalyst precursor contains ˜2.2 to 2.5 weight percent Ti, Mg/Ti molarratio of ˜5.5 to 6 and 25 to 30 weight percent Tetrahydrofuran electrondonor. The discrete catalyst precursor particles are mixed with mineraloil under a nitrogen atmosphere in a 400 liter vessel equipped with aturbine agitator to form a slurry containing approximately 28 weightpercent of the solid catalyst precursor.

Catalyst Precursor Partial Pre-Activation

Two separate pre-activation methods were used in the examples, batchpre-activation, or the more preferred in-line system, which allows forthe greatest flexibility in adjusting the pre-activation.

i) Batch Pre-Activation

The catalyst precursor slurry was added to a mixing vessel. Anappropriate amount of pre-activation agent (Lewis Acid (1), alsodissolved in mineral oil, is then added to the catalyst slurry ratioedto the amount of residual electron donor remaining in the catalystprecursor. The slurry was mixed for a minimum of one hour at atemperature of ˜35° C. The second Lewis Acid (2) is then added to theslurry, mixed and held for approximately 1 hour at a temperature of ˜35°C. All operations are carried out under high purity nitrogen atmosphereto prevent contamination of the pre-activated catalyst system. Theslurry was maintained under a nitrogen atmosphere at temperatures in the25° C. range to minimize deactivation upon storage. The catalyst slurrymay be used immediately in polymerization.

Batch pre-activation is used only for the inventive examples produced inpilot scale reactors, i.e. at polymer production rates of 15 to 30kg/hr. Use of the more preferred in-line system is not feasible due tothe very small flow rates of catalyst slurry (i.e. from 1 to 10 cc/hr oftotal catalyst flow) into the reactor which would require precisecontrol of very low liquid feed levels of the Lewis Acid components.

ii) In-Line Pre-Activation

The in line pre-activation system as described below:

(A) Preparing a slurry of a precursor and a viscous inert liquid, saidslurry having a viscosity of at least about 500 cp, the precursorcomprising (i) a ligand; (ii) a transition metal; and (iii) a firstLewis Base;

(B) Contacting the slurry of (A) with a first Lewis Acid such that atleast a portion of the Lewis Base is complexed with the Lewis Acidwherein the Lewis Acid has the formula MR_(n)X_((m−n)), M is Al, B orSi, R is a C1 to C14 alkyl or aryl radical, X is Cl, Br or I, m+nsatisfies the valency of the metal M, n is 0 to 3;

(C) Contacting the slurry of (B) with a second different Lewis Acid withthe formula MR_(n)X_((m−n)), M is Al, or B, R is a C1 to C14 alkyl oraryl radical, X is Cl, Br or I, m+n satisfies the valency of the metalM, n is 0 to 2;

(D) Feeding the slurry of (C) into a gas phase reactor.

The activator compounds were of the same concentration and type as thoseused for batch pre-activation, as described above.

Inventive PE Examples 1-14 and Comparative PE Examples 1-13

Inventive PE Examples 1-14 and Comparative PE Examples 1-13 wereprepared according to the following process based on the reactionconditions listed below in Table 2-6. Inventive PE Examples 1-14 andComparative PE Examples 1-13 were tested for their properties andresults are reported below in Table 2-7.

Polymerization Process

Products produced in pilot scale utilized the batch pre-activationprocess, as described above. Polymerization was conducted using a singlepolymerization with a 14 inch diameter straight side, a nominal 5 to 6foot bed height using a fluidization gas velocity of about 1.6 to 2.0feet/sec. Reactor polymerization conditions are given in the Tables 2-4.Triethylaluminum was used as cocatalyst.

Products from commercial scale reactors utilized the in-linepre-activation process, as described above. Commercial scale reactorsrange from 12 to 18 feet in diameter with bed height in the 50 to 60foot range. Polymerization rates ranged from 20,000 to 50,000 kg/hr.Reactor polymerization conditions are given in the Tables 5-6.Triethylaluminum was used as cocatalyst.

The precursors used contained 2.2 to 2.5 wt % Titanium, had a Mg/Ti moleratio of 5.5 to 6 and a Tetrahydrofuran content of 26 to 30 wt %.Precursor particle D50 was 23 to 25 microns and D10 was 8 to 10 microns.

Comparative 1-6, 8, and 10-13 were all obtained from commercial scalereactors using the in line pre-activation system. In all cases, thecatalyst was a 4520 (0.45 moles of DEAC added per mole of THF in thecatalyst precursor and 0.2 moles of TnHAL added per mole of THF in theprecursor). TnHAL was used as a 45 to 50 wt % solution in Hydrobrite 380mineral oil, DEAC was used as a 13 wt % solution in the same mineraloil. Pre-activation temperature was maintained at 35 to 40° C. Typicalreaction conditions are given in Table 5.

Inventive 1, 2, 5 and 7 to 9 were also produced in a commercial reactorusing the same catalyst precursor formulation with different catalystpre-activation parameters. Catalyst pre-activation parameters wereidentical. Tri-n-hexyl Aluminum was added at a 0.2 to 1 molar ratio tothe Tetrahydrofuran in the precursor composition in the first stage ofthe in-line preactivation system and diethylaluminum chloride in thesecond stage at a 0.7 to 1 molar ratio. TnHAL was used as a 45 to 50 wt% solution in Hydrobrite 380 mineral oil, DEAC was used as a 13 wt %solution in the same mineral oil. Preactivation temperature wasmaintained at 35 to 40° C. Typical reaction conditions are given inTable 6.

TABLE 2 Comparative 9 Inventive 12 Inventive 11 Lewis Acid 1 TnHAL TnHALTnHAL Lewis Acid 2 DEAC DEAC DEAC CATALYST J4520 (J_(i)) J4535 (J₁₂)J5535 (J₁₁) Reactor Temp. ° C. 95.0 95.0 95.0 Pressure, psig 347.0 347.3347.7 C2 Part. Pressure, psi 124.9 124.9 160.0 H2/C2 Molar Ratio 0.20110.2602 0.2425 C6/C2 Molar Ratio 0.0361 0.0361 0.0370 Isopentane mol %12.3 12.3 12.4 Production Rate pph 47.00 53.89 51.89 Residence Time, hr3.64 2.88 3.08 SGV (ft/sec) 1.70 1.66 1.65 RESIN PROPERTIES Melt IndexI₂ 1.91 1.93 1.83 Density, g/cm3 0.9432 0.9423 0.9423 Abbreviations:TnHAL = tri-n-hexylaluminum, TEAL = triethylaluminum, DEAC =diethylaluminumchloride. JXXYY = 0.01*XX or YY and is the molar ratio ofLewis Acid to THF contained in the catalyst precursor.

TABLE 3 Inventive 14 Inventive 13 Inventive 10 Lewis Acid1 TEAL TnHALTEAL Lewis Acid 2 DEAC DEAC DEAC CATALYST J4520 (J₁₄) J7020 (J₁₃) J7020(J₁₀) Temp. ° C. 95.0 95.0 95.0 Pressure, psig 347.7 347.9 347.9 C2Part. Pressure, psi 125.0 124.9 125.0 H2/C2 Molar Ratio 0.2549 0.25620.2476 C6/C2 Molar Ratio 0.0354 0.0368 0.0365 Isopentane mol % 12.4 12.412.0 Production Rate pph 59.33 51.89 46.83 Residence Time, hr 1.74 2.822.78 SGV (ft/sec) 1.67 1.65 1.69 RESIN PROPERTIES Melt Index I₂ 1.911.97 1.83 Density, g/cm3 0.9418 0.9400 0.9399

TABLE 4 Inventive Comparative 7 3 and 4¹ Inventive 6 Lewis Acid 1 TnHALTnHAL TEAL Lewis Acid 2 DEAC DEAC DEAC CATALYST J 4520 (J_(g)) J7020(J₃₋₄) J7020 (J₆) Temp. ° C. 95.0 95.0 95.0 Pressure, psig 347.9 348.2348.2 C2 Part. Pressure, psi 125.0 150.0 150.1 H2/C2 Molar Ratio 0.23460.2566 0.2565 C6/C2 Molar Ratio 0.0390 0.0384 0.0382 Isopentane mol %12.0 11.5 11.5 Production Rate 46.57 45.52 43.25 Residence Time, hr 3.193.25 3.64 SGV (ft/sec) 1.77 1.73 1.71 RESIN PROPERTIES Melt Index I₂1.96 1.99 1.95 Density, g/cm³ 0.9421 0.9414 0.9417 ¹Two differentsamples were obtained from this particular trial and both were evaluatedto demonstrate the reproducibility of the method.

TABLE 5 Catalyst Type J4520 J4520 REACTION CONDITIONS Temp. ° C. 92 to95 92 to 95 Pressure, kPA Average of 2250 Average of 2250 C2 Part.Pressure, kPA 850 to 900 850 to 900 H2/C2 Molar Ratio 0.24 to 0.25 ~0.22C6/C2 Molar Ratio 0.055 to 0.06  ~0.04 Isopentane mol %  7 to 10  7 to10 Production Rate, T/hr 35 to 50 35 to 50 Residence Time, hr 1.5 to 2  1.5 to 2   % Condensing >10 >10 SGV (m/s) 0.65 to 0.7  0.65 to 0.7 RESIN PROPERTIES Melt Index I₂ ~5.2 ~2.0 Density, g/cm3 ~0.9350 ~0.942

TABLE 6 Catalyst Type 7020 7020 REACTION CONDITIONS Temp. ° C. 92 to 9592 to 95 Pressure, kPA Average of 2250 Average of 2250 C2 Part.Pressure, kPA  900 to 1000  900 to 1000 H2/C2 Molar Ratio 0.24 to 0.25~0.22 C6/C2 Molar Ratio 0.055 to 0.06  ~0.04 Isopentane mol %  7 to 10 7 to 10 Production Rate, T/hr 35 to 50 35 to 50 Residence Time, hr 1.5to 2   1.5 to 2   % Condensing >10 >10 SGV (m/s) 0.65 to 0.7  0.65 to0.7  RESIN PROPERTIES Melt Index I₂ ~5.2 ~2.0 Density, g/cm3 ~0.9350~0.942

TABLE 7 Peak 1 Height Density MI Peak Height 1 Peak Height 2 RatioCatalyst Description 0.9420 2.00 0.000003175 0.000003244 0.9789 J_(a)Comparative 1 0.9420 2.00 0.000003154 0.000003251 0.9702 J_(b)Comparative 2 0.9420 2.00 0.090878256 0.097696759 0.9302 J_(c)Comparative 3 0.9420 2.00 0.092373677 0.099709436 0.9264 J_(d)Comparative 4 0.9420 2.00 0.092574991 0.099986590 0.9259 J_(e)Comparative 5 0.9420 2.00 0.090345763 0.098084159 0.9211 J_(f)Comparative 6 0.090396605 0.099728718 0.9064 J_(g) Comparative 7 0.94202.00 0.000003009 0.000003321 0.9060 J_(h) Comparative 8 0.0755500720.083887450 0.9006 J_(i) Comparative 9 0.9379 5.20 0.0000020550.000002305 0.8913 J_(j) Comparative 10 0.9350 5.20 0.0000021180.000002420 0.8751 J_(K) Comparative 11 0.9350 5.20 0.0000021060.000002426 0.8681 J_(l) Comparative 12 0.9350 5.20 0.0000021290.000002462 0.8648 J_(m) Comparative 13 0.9350 5.20 0.0000017730.000002307 0.7684 J₁ Inventive 1 0.9350 5.20 0.000001837 0.0000024420.7524 J₂ Inventive 2 0.000002475 0.000003303 0.7493 J₃ Inventive 30.072100000 0.097072303 0.7427 J₄ Inventive 4 0.9350 5.20 0.0000018180.000002452 0.7415 J₅ Inventive 5 0.072100000 0.100488424 0.7175 J₆Inventive 6 0.9350 5.20 0.000001693 0.000002410 0.7027 J₇ Inventive 70.9350 5.20 0.000001617 0.000002386 0.6775 J₈ Inventive 8 0.9350 5.200.000001625 0.000002407 0.6750 J₉ Inventive 9 0.055371292 0.0845731120.6547 J₁₀ Inventive 10 0.053466156 0.084165521 0.6353 J₁₁ Inventive 110.052961685 0.085543230 0.6191 J₁₂ Inventive 12 0.052469008 0.0867961200.6045 J₁₃ Inventive 13 0.048503831 0.084443480 0.5744 J₁₄ Inventive 14

Test Methods

Test methods include the following:

Density is measured in accordance with ASTM D-792.

Melt index I₂ measurements are performed according to ASTM 1)-1238,Condition 190°C./2.16 kilogram (kg). Melt index is reported as g/10minutes.

Triple Detector GPC (RAD GPC)

A high temperature Triple Detector Gel Permeation Chromatography(3D-GPC) system equipped with Robotic Assistant Delivery (RAD) systemfor sample preparation and sample injection. The concentration detectoris an Infra-red concentration detector (IR4 from Polymer Char, Valencia,Spain), which was used to determine the molecular weight and molecularweight distribution. Other two detectors are a Precision Detectors(Agilent) 2-angle laser light scattering detector, Model 2040, and a4-capillary differential viscometer detector, Model 150R (Malvern). The15° angle of the light scattering detector was used for calculationpurposes.

Data collection was performed using Polymer Char DM 100 Data acquisitionbox. The carrier solvent was 1,2,4-trichlorobenzene (TCB). The systemwas equipped with an on-line solvent degas device from Agilent. Thecolumn compartment was operated at 150° C. The columns were four MixedALS 30 cm, 20 micron columns. The samples were prepared at 2.0 mg/mLusing RAD system. The chromatographic solvent (TCB) and the samplepreparation solvent contained 200 ppm of butylated hydroxytoluene (BHT)and both solvent sources were nitrogen sparged. Polyethylene sampleswere stirred gently at 150° C. for 3 hours. The injection volume was 200μl, and the flow rate was 1.0 ml/minute.

Data was processed using in-house software. Calibration of the GPCcolumns was performed with 21 narrow molecular weight distributionpolystyrene standards. The molecular weights of the standards rangedfrom 580 to 8,400,000 g/mol, and were arranged in 6 “cocktail” mixtures,with at least a decade of separation between individual molecularweights.

The polystyrene standard peak molecular weights were converted topolyethylene molecular weights using the following equation (asdescribed in T. Willams and I. M. Ward, J. Polym. Sci., Polym. Let., 6,621 (1968)):

M _(polyethylene) =A(M _(polystyrene))^(B)   (1)

Here B has a value of 1.0, and the experimentally determined value of Ais 0.38.

A first order polynomial was used to fit the respectivepolyethylene-equivalent calibration points obtained from equation (1) totheir observed elution volumes. The actual polynomial fit was obtainedso as to relate the logarithm of polyethylene equivalent molecularweights to the observed elution volumes (and associated powers) for eachpolystyrene standard.

Number, weight, and z-average molecular weights were calculatedaccording to the following equations:

$\begin{matrix}{\overset{\_}{Mn} = \frac{\sum\limits^{i}{Wf}_{i}}{\sum\limits^{i}\left( {{Wf}_{i}\text{/}M_{i}} \right)}} & (2) \\{\overset{\_}{Mw} = \frac{\sum\limits^{i}\left( {{Wf}_{i}*M_{i}} \right)}{\sum\limits^{i}{Wf}_{i}}} & (3) \\{\overset{\_}{Mz} = \frac{\sum\limits^{i}\left( {{Wf}_{i}*M_{i}^{2}} \right)}{\sum\limits^{i}\left( {{Wf}_{i}*M_{i}} \right)}} & (4)\end{matrix}$

Where, Wf_(i) is the weight fraction of the i-th component and M_(i) isthe molecular weight of the i-th component.

The MWD was expressed as the ratio of the weight average molecularweight (Mw) to the number average molecular weight (Mn).

The A value was determined by adjusting A value in equation (1) untilMw, the weight average molecular weight calculated using equation (3)and the corresponding retention volume polynomial, agreed with theindependently determined value of Mw obtained in accordance with thelinear homopolymer reference with known weight average molecular weightof 115,000 g/mol.

The Systematic Approach for the determination of each detector offsetwas implemented in a manner consistent with that published by Balke,Mourey, et. al . (T. H. Mourey and S. T. Balke, in “Chromatography ofPolymers (ACS Symposium Series, #521)”, T. Provder Eds., An AmericanChemical Society Publication, 1993, Chpt 12, p. 180; S. T. Balke, R.Thitiratsakul, R. Lew, P. Cheung, T. H. Mourey, in “Chromatography ofPolymers (ACS Symposium Series, #521)”, T. Provder Eds., An AmericanChemical Society Publication, 1993, Chpt 13, p. 199), using dataobtained from the three detectors while analyzing the broad linearpolyethylene homopolymer (115,000 g/mol) and the narrow polystyrenestandards. The Systematic Approach was used to optimize each detectoroffset to give molecular weight results as close as possible to thoseobserved using the conventional GPC method. The overall injectedconcentration, used for the determinations of the molecular weight andintrinsic viscosity, was obtained from the sample infra-red area, andthe infra-red detector calibration (or mass constant) from the linearpolyethylene homopolymer of 115,000 g/mol. The chromatographicconcentrations were assumed low enough to eliminate addressing 2ndVirial coefficient effects (concentration effects on molecular weight).

The absolute molecular weight was calculated use the 15° laser lightscattering signal and the IR concentration detector,M_(PE,I, abs)=K_(LS)*(LS₁)/(IR₁) using the same K_(LS) calibrationconstant as in equation 8A. The paired data set of the i^(th) slice ofthe IR response and LS response was adjusted using the determinedoff-set as discussed in the Systematic Approach.

In addition to the above calculations, a set of alternative Mw, Mz andM_(z+1) [Mw (abs), Mz (abs), Mz (BB) and M_(z+1) (BB)] values were alsocalculated with the method proposed by Yau and Gillespie,(W. W. Yau andD. Gillespie, Polymer, 42, 8947-8958 (2001)), and determined from thefollowing equations:

$\begin{matrix}{{\overset{\_}{Mw}({abs})} = {K_{LS}*\frac{\sum\limits^{i}\left( {LS}_{i} \right)}{\sum\limits^{i}\left( {IR}_{i} \right)}}} & (5)\end{matrix}$

where, K_(LS)=LS−MW calibration constant. As explained before, theresponse factor, K_(LS), of the laser detector was determined using thecertificated value for the weight average molecular weight of NIST 1475(52,000 g/mol).

$\begin{matrix}{{\overset{\_}{Mz}({abs})} = \frac{\sum\limits^{i}{{IR}_{i}*\left( {{LS}_{i}\text{/}{IR}_{i}} \right)^{2}}}{\sum\limits^{i}{{IR}_{i}*\left( {{LS}_{i}\text{/}{IR}_{i}} \right)}}} & (6) \\{{\overset{\_}{Mz}({BB})} = \frac{\sum\limits^{i}\left( {{LS}_{i}*M_{i}} \right)}{\sum\limits^{i}\left( {LS}_{i} \right)}} & (7) \\{{\overset{\_}{M_{Z + 1}}({BB})} = \frac{\sum\limits^{i}\left( {{LS}_{i}*M_{i}^{2}} \right)}{\sum\limits^{i}\left( {{LS}_{i}*M_{i}} \right)}} & (8)\end{matrix}$

where LS_(i) is the 15 degree LS signal, and the M_(i) uses equation 2,and the LS detector alignment is as described previously.

In order to monitor the deviations over time, which may contain anelution component (caused by chromatographic changes) and a flow ratecomponent (caused by pump changes), a late eluting narrow peak isgenerally used as a “flow rate marker peak”. A flow rate marker wastherefore established based on a decane flow marker dissolved in theeluting sample prepared in TCB. This flow rate marker was used tolinearly correct the flow rate for all samples by alignment of thedecane peaks.

Procedure for Determining the GPC LALLS Peak Ratio

Obtain graphical and tabulated output data from GPC LALLS analysis.Using the graphical output, identify the narrow elution volume rangesthat bracket or contain the peaks observed on the curve. Each graph inFIG. 4 and FIG. 5 illustrates GPC LALLS curves with two distinct peaks.For each peak, one can assign an elution volume range that brackets orcontains the peak. In these illustrations, the areas of the peak can becontained within one elution volume. For each graph in FIG. 4 and FIG.5, the left peak is contained between 22 and 23 Elution Volumes. Theright peak is contained within 24.5 to 25.5 Elution Volumes. Forconvention, the highest molecular weight peak is designated Peak 1. Thelower molecular weight peak is designated Peak 2. Each graph in FIG. 4,FIG. 5, and FIG. 6 shows that the molecular weight decreases withincreasing elution volume. For these curves Peak 2, the lower molecularweight peak will be to the right of Peak 1.

There were instances when Peak 1 was not a not a distinct peak butrather a shoulder. The graph in FIG. 6 illustrates a curve with ashoulder. However, one experienced in the art could identify a narrowelution volume range that encompasses the shoulder and can bedifferentiated from Peak 2. In the graph in FIG. 6, Peak 1 can be seento be within 22 and 23 Elution Volumes. The shoulder area isdistinguished by a region proceeding it and following it with steeppositive slopes. The region of the shoulder approaches zero slope butdoes not reach zero. It will stay positive.

Within the region for each of these peaks (or shoulder), determine theminimum positive instantaneous slope and the elution volume where thatoccurs.

Equation for Determination of the Instantaneous Slope (m) Between GPCLALLS Data Points

$m = \frac{\left( {{Yi} - {Yj}} \right)}{\left( {{Xi} - {Xj}} \right)}$

Where Xi is the Elution Volume associated with the ith data point and Xjis the Elution Volume associated with the jth data point and where theith datapoint is the larger Elution Volume value and where Yi is the GPCLALLS output at Elution Volume Xi and Yj is the GPC LALLS output atElution Volume Xj.

The ith and jth sets of data points are adjacent data points on thecurve or in the tabulated data. If there is noise or scatter in the datathat results in discontinuous transitions from positive to negativeslope, than those data points should be used in the calculations.Typically smooth continuous regions and transitions are observed.

Once the m_(ij) is calculated for success set of data points withinregion identifies for each peak; the peak height can be determined foreach peak. Within the region for each of these peaks (or shoulder),determine the minimum positive instantaneous slope and the elutionvolume associated with that point. The Peak Height for that associatedpeak will be the GPC LALLS recorded output at that Elution Volume. Forstandard peaks, like that observed in FIGS. 1 and 2, the minimumpositive data point will typically be the last positive slope values. Itwill be followed by a continuous range of negative slope values. Forshoulders, such as in FIG. 3, the slopes do not go negative. Forshoulders, it is easier to identify a minimum by applying a movingaverage to the slope values. A guide for the moving average would be toselect the number of successive data points so that the span of ElutionVolumes would be about one quarter of the Elution Volume range for theshoulder. This approach will allow one to identify and select an ElutionVolume and the associated GPC LALLS output. The Peak Height will be theGPC LALLS output associated with the Elution Volume selected. Record thePeak Height associated with Peak 1 and Peak 2. The Peak Height Ratio iscalculated as follows:

Peak Height Ratio=PH1/PH1

Where PH1 is the GPC LALLS output associated Peak 1 and PH2 is the GPCLALLS output associated Peak 2.

The present invention may be embodied in other forms without departingfrom the spirit and the essential attributes thereof, and, accordingly,reference should be made to the appended claims, rather than to theforegoing specification, as indicating the scope of the invention.

1.5. (canceled)
 6. A process for polymerizing a polyethylene compositioncomprising the steps of: (A) Preparing a slurry of a precursor and aviscous inert liquid, said slurry having a viscosity of at least 500 cp,the precursor a formula Mg_(d)Me(OR)_(e)X_(f)(ED)_(g), wherein R is analiphatic or aromatic hydrocarbon radical having 1 to 14 carbon atoms orCOR′ wherein R′ is a aliphatic or aromatic hydrocarbon radical having 1to 14 carbon atoms, each OR group is the same or different; X isindependently chlorine, bromine, or iodine; ED is an electron donorchosen from an organic Lewis base; d is 0.5 to 56; e is 0, 1, or 2; f is2 to 116 and g is >1 to 20; Me is a transition metal selected from thegroup of titanium, zirconium, hafnium, and vanadium; (B) Contacting theslurry of (A) with a first Lewis Acid such that at least a portion ofthe organic Lewis Base is complexed with the first Lewis Acid whereinthe first Lewis Acid has the formula MR_(n)X_((m−n)), M is Al, B or Si,R is a C1 to C14 alkyl or aryl radical, X is Cl, Br or I, m+n satisfiesthe valency of the metal M, n is 0 to 3; (C) Contacting the slurry of(B) with a second different Lewis Acid with the formula MR_(n)X_((m−n)),M is Al, or B, R is a C1 to C14 alkyl or aryl radical, X is Cl, Br or I,m+n satisfies the valency of the metal M, n is 0 to 2; (D) Feeding theslurry of (C) into a gas phase reactor in which an olefin polymerizationreaction is in progress in the presence of one or more cocatalysts andwherein the molar ratios of the first Lewis Acid and second differentLewis Acid to the electron donor are controlled to affect specificfractions of the molecular weight distribution of the final polymerproduct; (E) Where both the relative ratio of the first Lewis Acid andsecond different Lewis Acid to electron donor and the chemical identityof the first Lewis Acid and second different Lewis Acid is adjusted topolymerize said polyethylene composition, wherein said polyethylenecomposition comprises at least 2 molecular weight distributions,measured via triple detector GPC low angle laser light scattering(GPC-LALLS), wherein each molecular weight distribution has a peak, andwherein measured detector response of peak 1 divided by the measureddetector response of peak 2 is in the range of from 0.50 to 0.79.
 7. Theprocess for polymerizing a polyethylene composition according to claim6, wherein the process occurs in a single gas phase reactor, or a dualgas phase reactor.
 8. An article comprising the polyethylene compositionproduced by the process of claim
 6. 9. The article of claim 8, whereinthe article is produced via rotational molding, thermoforming, blowmolding, or injection molding.